just bought a 02 gt, auto, all stock, seems like when cruising around 50mph, if i floor it, i get a quick "thump" from the back of the car. doesnt do it from dead stop, just when cruising at higher mph, any ideas where to start looking?

 

check your u joint and suspension bushings

 

I was thinking u joint. But its only at high speed. Would think u joints would be constant ??? I just bought the car. And the guy lived in boo foo on a dirt road so suspension might be spot on

 

Agree that it not happening from a stop or low speed doesn't make sense..., but loose control arm mount is my first guess. However, I would expect that to make noise besides just punching it at speed as well. The axle housing torques over under acceleration and changes the load on different components in the suspension.

While driving down the road, the u-joints are already under load so it shouldn't be a u-joint taking up slack.

Good luck locating the source of your noise!
Keep us posted on what you find.

 

Will do. I'm getting 4:10s and aluminum shaft. So hopefully I will see it when I'm down there

 

Take a good look at the torque boxes while you are under there as well.

You will love the improvement in acceleration with the 4.10 gears!!! You will find yourself rowing thru the gears a lot more quickly when pulling off from stop lights, etc.

 

I hope so!!! I was gonna go 373s. But a lot of people say if the auto to go 410s

 

If you have auto trans to go 410s. *

 

I see now that you had mentioned it being an auto trans.
You will like the 4.10 gears. They are a huge improvement over the stock ratio.

 

i sure hope so, 4.10s , and a tuner coming this week for sure!